Background: The deficiency of glucose-6-phosphate dehydrogenase enzyme (Glucose-6-phosphate dehydrogenase G6PD) is one of the genetic blood diseases. It is a disease related to the sex of the newborn, meaning that this disease is genetic disease linked to sex, and usually affects males more than females. Objective: The study aimed to evaluate the activity of some fatty acids and glucose-6-phosphate dehydrogenase enzyme in the blood of glucose-6-phosphate dehydrogenase deficient patients. Subjects and methods: The study was a group of 118 blood samples, 58 samples from healthy people (control), distributed as 34 males and 24 females in addition to 60 patients with glucose-6-phosphate dehydrogenase deficiency. The subjects were collected from the Outpatient Clinics in Baghdad City and Al-Dhuluiya district, Salah Al-Din district between 20/11/ 2020/ and 15/3/2021. The current study evaluated glucose-6-phosphate dehydrogenase enzyme activity, steroid hormones (Testosterone and dihydrotestosterone), Vit. D3, K, Ca, Cu and Zn in the serum of studied subjects. Results: There was a significant decrease in G-6-P-D in the blood serum of patients compared to the healthy group. Also, the results showed significant decrease in testosterone, DHEA, vit D3 and vit. k in the blood serum of patients compared to the healthy group. Additionally, the results showed that there was significant decrease in Zn in patients' blood serum compared to the healthy group. However, the results revealed an increase in Cu in the blood serum of patients when compared to the healthy group. Furthermore, the results revealed that there was no significant change in Ca between patients and healthy people.